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Sodium-24 is radioactive and can be created from common sodium-23 by neutron activation. With a half-life of 14.9560(15) h, 24 Na decays to 24 Mg by emission of an electron and two gamma rays. [10] [11] Exposure of the human body to intense neutron radiation creates 24 Na in the blood plasma.
A chart or table of nuclides maps the nuclear, or radioactive, behavior of nuclides, as it distinguishes the isotopes of an element.It contrasts with a periodic table, which only maps their chemical behavior, since isotopes (nuclides that are variants of the same element) do not differ chemically to any significant degree, with the exception of hydrogen.
Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable isotope is 23 Na. The free metal does not occur in nature and must be prepared from compounds. Sodium is the sixth most abundant element in the Earth's crust and exists in numerous minerals such as feldspars, sodalite, and halite (NaCl).
Neutrons are a necessary constituent of any atomic nucleus that contains more than one proton. As a result of their positive charges, interacting protons have a mutual electromagnetic repulsion that is stronger than their attractive nuclear interaction, so proton-only nuclei are unstable (see diproton and neutron–proton ratio). [32]
If the nucleus is assumed to be spherically symmetric, an approximate relationship between nuclear radius and mass number arises above A=40 from the formula R=R o A 1/3 with R o = 1.2 ± 0.2 fm. [6] R is the predicted spherical nuclear radius, A is the mass number, and R o is a constant determined by experimental data.
A neutron in free state is an unstable particle, with a half-life around ten minutes. It undergoes β − decay (a type of radioactive decay) by turning into a proton while emitting an electron and an electron antineutrino. This reaction can occur because the mass of the neutron is slightly greater than that of the proton.
An example is calcium-40, with 20 neutrons and 20 protons, which is the heaviest stable isotope made of the same number of protons and neutrons. Both calcium-48 and nickel-48 are doubly magic because calcium-48 has 20 protons and 28 neutrons while nickel-48 has 28 protons and 20 neutrons. Calcium-48 is very neutron-rich for such a relatively ...
The neutron–proton ratio (N/Z ratio or nuclear ratio) of an atomic nucleus is the ratio of its number of neutrons to its number of protons. Among stable nuclei and naturally occurring nuclei, this ratio generally increases with increasing atomic number. [ 1 ]